Why did he say "Mah Gadlu Ma'asecha"?
Radak: When I contemplate Your actions, I recognize that they are too great to fully understand them. Also refer to 92:8:2:1*.
Why did he say "Amku Machshevosecha"?
Radak: Chachamim did not discover reasons for the world - hard questions why the world is one way and not another way. One of them is why He created it at the time that he did, and not before 1 . The answer is - so decreed His Chachmah, and we do not know His thoughts. They are deep below and great above! Also refer to 92:8:2:1*.
Malbim: This explains why Hashem divided conduct - sometimes it is nature, and sometimes Hashgachah. Why did He put in their hearts, that man does not always recognize Hashgachah, and many think that everything goes according to nature? This was a deep thought - to leave room for choice, and reward and punishment. If He would always immediately punish a Rasha, and conduct via Hashgachah was evident, people would fear to do evil, and there would be no choice. Your natural ordered acts are great, but Your thoughts about this are very deep, that conduct according to Hashgachah will be hidden.
Really, time does not apply to Hashem Himself. Human intellect cannot understand how at some 'time' Hashem began the process of creating worlds that were Mishtalshel and eventually led to this world (heard from R. Meir Eliyahu).
